This is an easy question but I would like to be sure I am doing things as intended.

I know that in order to consider only part of a dataset I should use DataSetFilter:
Code:

DataSetFilter myFilter = CreateFilter (myData,1,"", "", "" ); 

This will take into consideration all the positions in the alignment. However it is possible that I may only want to run the analysis for the first column in my DataSet (a multiple sequence alignment). If for example I only want to consider the first position in the alignment, I should use:
Code:

DataSetFilter myFilter = CreateFilter (myData,1,"1", "", "" ); 

Regarding the former, here is my question: Which number correspond to the first position in a DataSet? Is it 0 (zero) or 1 (one)?